[PATCH 2/9] ext4: generalize EXT4_GET_BLOCKS_IO_SUBMIT flag usage

[Zhang Yi <yi.zhang@huaweicloud.com>]

From: Zhang Yi <yi.zhang@huawei.com>

Currently, the EXT4_GET_BLOCKS_IO_SUBMIT flag is only used during data
writeback to indicate that in ordered mode, the journal commit thread
should skip re-submitting data and simply wait for I/O completion.

To prepare for later patches that need to detect I/O submission context
in ext4_map_blocks(), generalizes the meaning of
EXT4_GET_BLOCKS_IO_SUBMIT. This flag will be set during:
 1) data I/O writeback,
 2) I/O completion extents conversion,
 3) journal performing commit in fast_commit.

This change doesn't affect current usage of this flag and provides a
clear way to identify I/O submission context.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
 fs/ext4/ext4.h        | 13 ++++++++-----
 fs/ext4/fast_commit.c |  3 ++-
 2 files changed, 10 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 5a20e9cd7184..ad39bfe4b5d2 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -706,9 +706,6 @@ enum {
 #define EXT4_GET_BLOCKS_CONVERT			0x0010
 #define EXT4_GET_BLOCKS_IO_CREATE_EXT		(EXT4_GET_BLOCKS_PRE_IO|\
 					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)
-	/* Convert extent to initialized after IO complete */
-#define EXT4_GET_BLOCKS_IO_CONVERT_EXT		(EXT4_GET_BLOCKS_CONVERT|\
-					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT)
 	/* Eventual metadata allocation (due to growing extent tree)
 	 * should not fail, so try to use reserved blocks for that.*/
 #define EXT4_GET_BLOCKS_METADATA_NOFAIL		0x0020
@@ -720,9 +717,15 @@ enum {
 #define EXT4_GET_BLOCKS_ZERO			0x0200
 #define EXT4_GET_BLOCKS_CREATE_ZERO		(EXT4_GET_BLOCKS_CREATE |\
 					EXT4_GET_BLOCKS_ZERO)
-	/* Caller will submit data before dropping transaction handle. This
-	 * allows jbd2 to avoid submitting data before commit. */
+	/* Caller is in the context of data submission, such as writeback,
+	 * fsync, etc. Especially, in the generic writeback path, caller will
+	 * submit data before dropping transaction handle. This allows jbd2
+	 * to avoid submitting data before commit. */
 #define EXT4_GET_BLOCKS_IO_SUBMIT		0x0400
+	/* Convert extent to initialized after IO complete */
+#define EXT4_GET_BLOCKS_IO_CONVERT_EXT		(EXT4_GET_BLOCKS_CONVERT |\
+					 EXT4_GET_BLOCKS_CREATE_UNWRIT_EXT |\
+					 EXT4_GET_BLOCKS_IO_SUBMIT)
 	/* Caller is in the atomic contex, find extent if it has been cached */
 #define EXT4_GET_BLOCKS_CACHED_NOWAIT		0x0800
 
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index da4263a14a20..11c42b39478b 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -910,7 +910,8 @@ static int ext4_fc_write_inode_data(struct inode *inode, u32 *crc)
 	while (cur_lblk_off <= new_blk_size) {
 		map.m_lblk = cur_lblk_off;
 		map.m_len = new_blk_size - cur_lblk_off + 1;
-		ret = ext4_map_blocks(NULL, inode, &map, 0);
+		ret = ext4_map_blocks(NULL, inode, &map,
+				      EXT4_GET_BLOCKS_IO_SUBMIT);
 		if (ret < 0)
 			return -ECANCELED;
 
-- 
2.46.1